Enhancement of hydrogen embrittlement resistance of Fe-Mn-C twinning-induced plasticity steel by partial recrystallization technique

Highlights: • The partially recrystallized structure was obtained by annealing time control. • The unrecrystallized grains had the high density of dislocation and mechanical twins. • The partial recrystallization had the better H resistance than full recrystallization. • The dislocation and twins in unrecrystallized grain trapped the diffusible H. -- Abstract: We suggest that the partial recrystallization is a novel pathway to increase the hydrogen embrittlement resistance of Fe-Mn-C twinning-induced plasticity steels. The Fe-18Mn-0.6C (wt%) cold-rolled steel was annealed for from 3 min to 30 min at 650 °C. When the annealing time was shorter than 5 min, the specimen was partially recrystallized, while when the annealing time exceeded 10 min, the matrix was almost fully recrystallized. The partially recrystallized specimens exhibited the improved hydrogen embrittlement resistance because the inherited dislocation and mechanical twins in unrecrytallized grains acted as a trap site for diffusible hydrogen.